Large enhancement of thermopower at low magnetic field in compensated Dirac/Weyl semimetals

We theoretically study the thermoelectric properties of compensated Dirac/Weyl semimetals subjected to a magnetic field. Previous work has shown that Dirac/Weyl semimetals without compensation can exhibit a large enhancement of thermopower in the extreme quantum limit of magnetic field. Here we show that in compensated systems a huge enhancement of thermopower can be obtained even at much smaller magnetic field, provided that ω_cτ » 1. We discuss our results in light of recent measurements on the compensated Weyl semimetal tantalum phosphide, in which an enormous magnetothermoelectric effect was observed.